Field of the Invention
Embodiments of the present invention relate to post-processing apparatuses, image forming systems, and post-processing methods that enable case bookbinding.
Description of the Related Art
Where a case work is created with sheets having images formed thereon, bookbinding is performed such that paste is applied along the back portion of a book body and a cover is adhesively bonded thereto. In applying paste, the paste is preferably applied plentifully in terms of increasing durability and preventing missing of leaves due to pulling off. As depicted in FIG. 14, however, plentiful application of paste causes a considerable amount of paste overflow at a side portion of a booklet S, and the overflow of paste G is visible when a cover C is opened, degrading the quality of the booklet. Hence, the amount of application of paste is suppressed, such that the paste G does not overflow onto the booklet S while durability of the booklet is maintained.
For example, the following techniques are known for optimizing the amount of application of paste.
According to JP 2011-000773 A, an apparatus is disclosed which has information on an optimal amount of paste to be applied per medium and is configured to apply paste according to the paste amount in the information.
According to JP 2009-285923 A, a bookbinding apparatus is disclosed which is configured to increase the amount of application of paste in applying paste to a booklet treated with roughening, so as to increase binding strength.
According to JP 2009-078424 A, a bookbinding apparatus is disclosed which is configured to adjust the coating thickness of a paste layer on the basis of the thickness of a sheet bundle, based on information on a booklet including information about the paper thickness of sheets comprising the sheet bundle, paper size information, weight information, and sheet type information.
In case of case bookbinding, however, the cover sometimes has a gutter (in the vicinity of the bound portion where the booklet is in a spread state). In such a case, the quality is not degraded as depicted in FIG. 14 when the cover is opened, even if the paste overflows toward a side of the booklet S. Rather, no paste overflow toward a side degrades the quality, since the guttered portion easily peels off.